Substrate carriers configured for holding multiple hard disk substrates during fabrication and shipping are well known in the data storage device industry. Examples of such prior art carriers are described in U.S. Pat. Nos. 5,921,397; 5,704,494; 4,669,612; and 5,348,151, each of which is hereby fully incorporated herein by reference.
During processing of hard disks using known prior art carriers or cassettes, a typical practice involves mechanical polishing of the disks at various polishing stations. Typically, handling of the disk carriers or cassettes during various fabrication processing steps is generally automated. A relatively high degree of precision in carrier or cassette positioning is desirable to minimize disk damage and particulate generation from improper indexing of the robotic tooling. Prior art carriers or cassettes, while offering a generally workable degree of precision in positioning, are still sometimes mispositioned, resulting in disk damage or excessive particulates in the processing environment. In addition, certain aspects of the mechanical polishing process require the manual loading of each individual disk into the prior art carriers or cassettes.
As with many disk handling processes, however, unloading and loading disks into cassettes may cause damage to the disks. Such damage may render one or more disks unusable, thereby reducing production yield and increasing manufacturing cost. One substantial cause of disk damage stems from the insertion of disks into the narrow slots of the cassette. Due to several factors, including the thinness of the disks and the close proximity of the slots, it is likely that a disk may be incorrectly inserted into the cassette. For example, a disk could be inadvertently placed into an occupied slot. The placement of a disk into an occupied slot may likely cause damage to both the disk being inserted and to the disk residing in the slot.
For example, a manual polishing station requires an operator to manually load disks that have been polished into disk cassettes. The operator must aim and align the individual disk before inserting it vertically into the disk cassette for storage or transportation. The manual handling of the disks often yields poor quality disks due to disk-to-disk contact. It would, therefore, be desirable to develop an apparatus and method to prevent damage to disks while inserting a disk into a cassette. What is needed in the industry is a disk storage assembly including a disk cassette and a disk slotter that addresses the above-identified deficiencies in the prior art carriers or cassettes.